cJSON使用说明
1.下载链接
DaveGamble/cJSON：ANSI C 语言中的超轻量级 JSON 解析器
GitHub - DaveGamble/cJSON: Ultralightweight JSON parser in ANSI C
git clone https://github.com/DaveGamble/cJSON.git
2.只需导入
cJSON/cJSON.c cJSON/cJSON.h
3.API讲解
/* cJSON Types: */
#define cJSON_Invalid (0)
#define cJSON_False (1 << 0)
#define cJSON_True (1 << 1)
#define cJSON_NULL (1 << 2)
#define cJSON_Number (1 << 3)
#define cJSON_String (1 << 4)
#define cJSON_Array (1 << 5)
#define cJSON_Object (1 << 6)
#define cJSON_Raw (1 << 7) /* raw json */
#define cJSON_IsReference 256
#define cJSON_StringIsConst 512
/* The cJSON structure: */
typedef struct cJSON
{
/* next/prev allow you to walk array/object chains. Alternatively, use GetArraySize/GetArrayItem/GetObjectItem */
struct cJSON *next;
struct cJSON *prev;
/* An array or object item will have a child pointer pointing to a chain of the items in the array/object. */
struct cJSON *child;
/* The type of the item, as above. */
int type;
/* The item's string, if type==cJSON_String and type == cJSON_Raw */
char *valuestring;
/* writing to valueint is DEPRECATED, use cJSON_SetNumberValue instead */
int valueint;
/* The item's number, if type==cJSON_Number */
double valuedouble;
/* The item's name string, if this item is the child of, or is in the list of subitems of an object. */
char *string;
} cJSON;
typedef struct cJSON_Hooks
{
/* malloc/free are CDECL on Windows regardless of the default calling convention of the compiler, so ensure the hooks allow passing those functions directly. */
void *(CJSON_CDECL *malloc_fn)(size_t sz);
void (CJSON_CDECL *free_fn)(void *ptr);
} cJSON_Hooks;
typedef int cJSON_bool;
/* Limits how deeply nested arrays/objects can be before cJSON rejects to parse them.
* This is to prevent stack overflows. */
#ifndef CJSON_NESTING_LIMIT
#define CJSON_NESTING_LIMIT 1000
#endif
/* Limits the length of circular references can be before cJSON rejects to parse them.
* This is to prevent stack overflows. */
#ifndef CJSON_CIRCULAR_LIMIT
#define CJSON_CIRCULAR_LIMIT 10000
#endif
/* returns the version of cJSON as a string */
CJSON_PUBLIC(const char*) cJSON_Version(void);
/* Supply malloc, realloc and free functions to cJSON */
CJSON_PUBLIC(void) cJSON_InitHooks(cJSON_Hooks* hooks);
/* Memory Management: the caller is always responsible to free the results from all variants of cJSON_Parse (with cJSON_Delete) and cJSON_Print (with stdlib free, cJSON_Hooks.free_fn, or cJSON_free as appropriate). The exception is cJSON_PrintPreallocated, where the caller has full responsibility of the buffer. */
/* Supply a block of JSON, and this returns a cJSON object you can interrogate. */
CJSON_PUBLIC(cJSON *) cJSON_Parse(const char *value);
CJSON_PUBLIC(cJSON *) cJSON_ParseWithLength(const char *value, size_t buffer_length);
/* ParseWithOpts allows you to require (and check) that the JSON is null terminated, and to retrieve the pointer to the final byte parsed. */
/* If you supply a ptr in return_parse_end and parsing fails, then return_parse_end will contain a pointer to the error so will match cJSON_GetErrorPtr(). */
CJSON_PUBLIC(cJSON *) cJSON_ParseWithOpts(const char *value, const char **return_parse_end, cJSON_bool require_null_terminated);
CJSON_PUBLIC(cJSON *) cJSON_ParseWithLengthOpts(const char *value, size_t buffer_length, const char **return_parse_end, cJSON_bool require_null_terminated);
/* Render a cJSON entity to text for transfer/storage. */
CJSON_PUBLIC(char *) cJSON_Print(const cJSON *item);
/* Render a cJSON entity to text for transfer/storage without any formatting. */
CJSON_PUBLIC(char *) cJSON_PrintUnformatted(const cJSON *item);
/* Render a cJSON entity to text using a buffered strategy. prebuffer is a guess at the final size. guessing well reduces reallocation. fmt=0 gives unformatted, =1 gives formatted */
CJSON_PUBLIC(char *) cJSON_PrintBuffered(const cJSON *item, int prebuffer, cJSON_bool fmt);
/* Render a cJSON entity to text using a buffer already allocated in memory with given length. Returns 1 on success and 0 on failure. */
/* NOTE: cJSON is not always 100% accurate in estimating how much memory it will use, so to be safe allocate 5 bytes more than you actually need */
CJSON_PUBLIC(cJSON_bool) cJSON_PrintPreallocated(cJSON *item, char *buffer, const int length, const cJSON_bool format);
/* Delete a cJSON entity and all subentities. */
CJSON_PUBLIC(void) cJSON_Delete(cJSON *item);
/* Returns the number of items in an array (or object). */
CJSON_PUBLIC(int) cJSON_GetArraySize(const cJSON *array);
/* Retrieve item number "index" from array "array". Returns NULL if unsuccessful. */
CJSON_PUBLIC(cJSON *) cJSON_GetArrayItem(const cJSON *array, int index);
/* Get item "string" from object. Case insensitive. */
CJSON_PUBLIC(cJSON *) cJSON_GetObjectItem(const cJSON * const object, const char * const string);
CJSON_PUBLIC(cJSON *) cJSON_GetObjectItemCaseSensitive(const cJSON * const object, const char * const string);
CJSON_PUBLIC(cJSON_bool) cJSON_HasObjectItem(const cJSON *object, const char *string);
/* For analysing failed parses. This returns a pointer to the parse error. You'll probably need to look a few chars back to make sense of it. Defined when cJSON_Parse() returns 0. 0 when cJSON_Parse() succeeds. */
CJSON_PUBLIC(const char *) cJSON_GetErrorPtr(void);
/* Check item type and return its value */
CJSON_PUBLIC(char *) cJSON_GetStringValue(const cJSON * const item);
CJSON_PUBLIC(double) cJSON_GetNumberValue(const cJSON * const item);
/* These functions check the type of an item */
CJSON_PUBLIC(cJSON_bool) cJSON_IsInvalid(const cJSON * const item);
CJSON_PUBLIC(cJSON_bool) cJSON_IsFalse(const cJSON * const item);
CJSON_PUBLIC(cJSON_bool) cJSON_IsTrue(const cJSON * const item);
CJSON_PUBLIC(cJSON_bool) cJSON_IsBool(const cJSON * const item);
CJSON_PUBLIC(cJSON_bool) cJSON_IsNull(const cJSON * const item);
CJSON_PUBLIC(cJSON_bool) cJSON_IsNumber(const cJSON * const item);
CJSON_PUBLIC(cJSON_bool) cJSON_IsString(const cJSON * const item);
CJSON_PUBLIC(cJSON_bool) cJSON_IsArray(const cJSON * const item);
CJSON_PUBLIC(cJSON_bool) cJSON_IsObject(const cJSON * const item);
CJSON_PUBLIC(cJSON_bool) cJSON_IsRaw(const cJSON * const item);
/* These calls create a cJSON item of the appropriate type. */
CJSON_PUBLIC(cJSON *) cJSON_CreateNull(void);
CJSON_PUBLIC(cJSON *) cJSON_CreateTrue(void);
CJSON_PUBLIC(cJSON *) cJSON_CreateFalse(void);
CJSON_PUBLIC(cJSON *) cJSON_CreateBool(cJSON_bool boolean);
CJSON_PUBLIC(cJSON *) cJSON_CreateNumber(double num);
CJSON_PUBLIC(cJSON *) cJSON_CreateString(const char *string);
/* raw json */
CJSON_PUBLIC(cJSON *) cJSON_CreateRaw(const char *raw);
CJSON_PUBLIC(cJSON *) cJSON_CreateArray(void);
CJSON_PUBLIC(cJSON *) cJSON_CreateObject(void);
/* Create a string where valuestring references a string so
* it will not be freed by cJSON_Delete */
CJSON_PUBLIC(cJSON *) cJSON_CreateStringReference(const char *string);
/* Create an object/array that only references it's elements so
* they will not be freed by cJSON_Delete */
CJSON_PUBLIC(cJSON *) cJSON_CreateObjectReference(const cJSON *child);
CJSON_PUBLIC(cJSON *) cJSON_CreateArrayReference(const cJSON *child);
/* These utilities create an Array of count items.
* The parameter count cannot be greater than the number of elements in the number array, otherwise array access will be out of bounds.*/
CJSON_PUBLIC(cJSON *) cJSON_CreateIntArray(const int *numbers, int count);
CJSON_PUBLIC(cJSON *) cJSON_CreateFloatArray(const float *numbers, int count);
CJSON_PUBLIC(cJSON *) cJSON_CreateDoubleArray(const double *numbers, int count);
CJSON_PUBLIC(cJSON *) cJSON_CreateStringArray(const char *const *strings, int count);
/* Append item to the specified array/object. */
CJSON_PUBLIC(cJSON_bool) cJSON_AddItemToArray(cJSON *array, cJSON *item);
CJSON_PUBLIC(cJSON_bool) cJSON_AddItemToObject(cJSON *object, const char *string, cJSON *item);
/* Use this when string is definitely const (i.e. a literal, or as good as), and will definitely survive the cJSON object.
* WARNING: When this function was used, make sure to always check that (item->type & cJSON_StringIsConst) is zero before
* writing to `item->string` */
CJSON_PUBLIC(cJSON_bool) cJSON_AddItemToObjectCS(cJSON *object, const char *string, cJSON *item);
/* Append reference to item to the specified array/object. Use this when you want to add an existing cJSON to a new cJSON, but don't want to corrupt your existing cJSON. */
CJSON_PUBLIC(cJSON_bool) cJSON_AddItemReferenceToArray(cJSON *array, cJSON *item);
CJSON_PUBLIC(cJSON_bool) cJSON_AddItemReferenceToObject(cJSON *object, const char *string, cJSON *item);
/* Remove/Detach items from Arrays/Objects. */
CJSON_PUBLIC(cJSON *) cJSON_DetachItemViaPointer(cJSON *parent, cJSON * const item);
CJSON_PUBLIC(cJSON *) cJSON_DetachItemFromArray(cJSON *array, int which);
CJSON_PUBLIC(void) cJSON_DeleteItemFromArray(cJSON *array, int which);
CJSON_PUBLIC(cJSON *) cJSON_DetachItemFromObject(cJSON *object, const char *string);
CJSON_PUBLIC(cJSON *) cJSON_DetachItemFromObjectCaseSensitive(cJSON *object, const char *string);
CJSON_PUBLIC(void) cJSON_DeleteItemFromObject(cJSON *object, const char *string);
CJSON_PUBLIC(void) cJSON_DeleteItemFromObjectCaseSensitive(cJSON *object, const char *string);
/* Update array items. */
CJSON_PUBLIC(cJSON_bool) cJSON_InsertItemInArray(cJSON *array, int which, cJSON *newitem); /* Shifts pre-existing items to the right. */
CJSON_PUBLIC(cJSON_bool) cJSON_ReplaceItemViaPointer(cJSON * const parent, cJSON * const item, cJSON * replacement);
CJSON_PUBLIC(cJSON_bool) cJSON_ReplaceItemInArray(cJSON *array, int which, cJSON *newitem);
CJSON_PUBLIC(cJSON_bool) cJSON_ReplaceItemInObject(cJSON *object,const char *string,cJSON *newitem);
CJSON_PUBLIC(cJSON_bool) cJSON_ReplaceItemInObjectCaseSensitive(cJSON *object,const char *string,cJSON *newitem);
/* Duplicate a cJSON item */
CJSON_PUBLIC(cJSON *) cJSON_Duplicate(const cJSON *item, cJSON_bool recurse);
/* Duplicate will create a new, identical cJSON item to the one you pass, in new memory that will
* need to be released. With recurse!=0, it will duplicate any children connected to the item.
* The item->next and ->prev pointers are always zero on return from Duplicate. */
/* Recursively compare two cJSON items for equality. If either a or b is NULL or invalid, they will be considered unequal.
* case_sensitive determines if object keys are treated case sensitive (1) or case insensitive (0) */
CJSON_PUBLIC(cJSON_bool) cJSON_Compare(const cJSON * const a, const cJSON * const b, const cJSON_bool case_sensitive);
/* Minify a strings, remove blank characters(such as ' ', '\t', '\r', '\n') from strings.
* The input pointer json cannot point to a read-only address area, such as a string constant,
* but should point to a readable and writable address area. */
CJSON_PUBLIC(void) cJSON_Minify(char *json);
/* Helper functions for creating and adding items to an object at the same time.
* They return the added item or NULL on failure. */
CJSON_PUBLIC(cJSON*) cJSON_AddNullToObject(cJSON * const object, const char * const name);
CJSON_PUBLIC(cJSON*) cJSON_AddTrueToObject(cJSON * const object, const char * const name);
CJSON_PUBLIC(cJSON*) cJSON_AddFalseToObject(cJSON * const object, const char * const name);
CJSON_PUBLIC(cJSON*) cJSON_AddBoolToObject(cJSON * const object, const char * const name, const cJSON_bool boolean);
CJSON_PUBLIC(cJSON*) cJSON_AddNumberToObject(cJSON * const object, const char * const name, const double number);
CJSON_PUBLIC(cJSON*) cJSON_AddStringToObject(cJSON * const object, const char * const name, const char * const string);
CJSON_PUBLIC(cJSON*) cJSON_AddRawToObject(cJSON * const object, const char * const name, const char * const raw);
CJSON_PUBLIC(cJSON*) cJSON_AddObjectToObject(cJSON * const object, const char * const name);
CJSON_PUBLIC(cJSON*) cJSON_AddArrayToObject(cJSON * const object, const char * const name);
/* When assigning an integer value, it needs to be propagated to valuedouble too. */
#define cJSON_SetIntValue(object, number) ((object) ? (object)->valueint = (object)->valuedouble = (number) : (number))
/* helper for the cJSON_SetNumberValue macro */
CJSON_PUBLIC(double) cJSON_SetNumberHelper(cJSON *object, double number);
#define cJSON_SetNumberValue(object, number) ((object != NULL) ? cJSON_SetNumberHelper(object, (double)number) : (number))
/* Change the valuestring of a cJSON_String object, only takes effect when type of object is cJSON_String */
CJSON_PUBLIC(char*) cJSON_SetValuestring(cJSON *object, const char *valuestring);
/* If the object is not a boolean type this does nothing and returns cJSON_Invalid else it returns the new type*/
#define cJSON_SetBoolValue(object, boolValue) ( \
(object != NULL && ((object)->type & (cJSON_False|cJSON_True))) ? \
(object)->type=((object)->type &(~(cJSON_False|cJSON_True)))|((boolValue)?cJSON_True:cJSON_False) : \
cJSON_Invalid\
)
/* Macro for iterating over an array or object */
#define cJSON_ArrayForEach(element, array) for(element = (array != NULL) ? (array)->child : NULL; element != NULL; element = element->next)
/* malloc/free objects using the malloc/free functions that have been set with cJSON_InitHooks */
CJSON_PUBLIC(void *) cJSON_malloc(size_t size);
CJSON_PUBLIC(void) cJSON_free(void *object);
4.使用
4.1 cJSON_Parse
CJSON_PUBLIC(cJSON *) cJSON_Parse(const char *value); CJSON_PUBLIC(cJSON *) cJSON_ParseWithLength(const char *value, size_t buffer_length); /* ParseWithOpts allows you to require (and check) that the JSON is null terminated, and to retrieve the pointer to the final byte parsed. */ /* If you supply a ptr in return_parse_end and parsing fails, then return_parse_end will contain a pointer to the error so will match cJSON_GetErrorPtr(). */ CJSON_PUBLIC(cJSON *) cJSON_ParseWithOpts(const char *value, const char **return_parse_end, cJSON_bool require_null_terminated); CJSON_PUBLIC(cJSON *) cJSON_ParseWithLengthOpts(const char *value, size_t buffer_length, const char **return_parse_end, cJSON_bool require_null_terminated);
4.2 cJSON_Print
/* Render a cJSON entity to text for transfer/storage. */ CJSON_PUBLIC(char *) cJSON_Print(const cJSON *item); /* Render a cJSON entity to text for transfer/storage without any formatting. */ CJSON_PUBLIC(char *) cJSON_PrintUnformatted(const cJSON *item); /* Render a cJSON entity to text using a buffered strategy. prebuffer is a guess at the final size. guessing well reduces reallocation. fmt=0 gives unformatted, =1 gives formatted */ CJSON_PUBLIC(char *) cJSON_PrintBuffered(const cJSON *item, int prebuffer, cJSON_bool fmt); /* Render a cJSON entity to text using a buffer already allocated in memory with given length. Returns 1 on success and 0 on failure. */ /* NOTE: cJSON is not always 100% accurate in estimating how much memory it will use, so to be safe allocate 5 bytes more than you actually need */ CJSON_PUBLIC(cJSON_bool) cJSON_PrintPreallocated(cJSON *item, char *buffer, const int length, const cJSON_bool format);
4.2.1 cJSON_Print
#include <stdio.h>
#include <cjson/cjson.h>
int main() {
cJSON *root = cJSON_CreateObject();
cJSON_AddItemToObject(root, "name", cJSON_CreateString("John"));
cJSON_AddItemToObject(root, "age", cJSON_CreateNumber(30));
char *json_string = cJSON_Print(root);
printf("%s\n", json_string);
// 释放内存
cJSON_free(root);
free(json_string);
return 0;
}
4.2.2 cJSON_PrintUnformatted
#include <stdio.h>
#include <cjson/cjson.h>
int main() {
cJSON *root = cJSON_CreateObject();
cJSON_AddItemToObject(root, "name", cJSON_CreateString("John"));
cJSON_AddItemToObject(root, "age", cJSON_CreateNumber(30));
char *json_string = cJSON_PrintUnformatted(root);
printf("%s\n", json_string);
cJSON_free(root);
free(json_string);
return 0;
}
4.2.3 cJSON_PrintBuffered
#include <stdio.h>
#include <cjson/cjson.h>
int main() {
cJSON *root = cJSON_CreateObject();
// 假设这里添加了大量的键值对到root对象中
// 预估字符串大小为1024字节
int prebuffer = 1024;
char *json_string = cJSON_PrintBuffered(root, prebuffer, 1);
printf("%s\n", json_string);
cJSON_free(root);
free(json_string);
return 0;
}
4.2.4 cJSON_PrintPreallocated
#include <stdio.h>
#include <cjson/cjson.h>
int main() {
cJSON *root = cJSON_CreateObject();
cJSON_AddItemToObject(root, "name", cJSON_CreateString("John"));
cJSON_AddItemToObject(root, "age", cJSON_CreateNumber(30));
// 假设预先分配了200字节的缓冲区
char buffer[200];
cJSON_bool success = cJSON_PrintPreallocated(root, buffer, sizeof(buffer), 1);
if (success) {
printf("%s\n", buffer);
} else {
printf("Error: Failed to print cJSON to preallocated buffer.\n");
}
cJSON_free(root);
return 0;
}
4.3
4.3.1 cJSON_Delete
#include <stdio.h>
#include "cJSON.h"
int main() {
const char *json_string = "{\"name\":\"John\", \"age\":30}";
cJSON *root = cJSON_Parse(json_string);
if (root) {
// 在这里可以对解析后的JSON数据进行操作
//...
// 操作完成后，删除整个JSON结构
cJSON_Delete(root);
}
return 0;
}
4.3.2 cJSON_GetArraySize
#include <stdio.h>
#include "cJSON.h"
int main() {
const char *json_string = "[1, 2, 3, 4, 5]";
cJSON *root = cJSON_Parse(json_string);
if (root && cJSON_IsArray(root)) {
int size = cJSON_GetArraySize(root);
for (int i = 0; i < size; i++) {
cJSON *item = cJSON_GetArrayItem(root, i);
if (cJSON_IsNumber(item)) {
printf("%d ", item->valueint);
}
}
cJSON_Delete(root);
}
return 0;
}
4.3.3 cJSON_GetArrayItem
#include <stdio.h>
#include "cJSON.h"
int main() {
const char *json_string = "[\"apple\", \"banana\", \"cherry\"]";
cJSON *root = cJSON_Parse(json_string);
if (root && cJSON_IsArray(root)) {
cJSON *item = cJSON_GetArrayItem(root, 1);
if (item) {
printf("The second item in the array is: %s\n", item->valuestring);
}
cJSON_Delete(root);
}
return 0;
}
4.3.4 cJSON_GetObjectItem
#include <stdio.h>
#include "cJSON.h"
int main() {
const char *json_string = "{\"NaMe\":\"John\", \"AGE\":30}";
cJSON *root = cJSON_Parse(json_string);
if (root && cJSON_IsObject(root)) {
cJSON *name = cJSON_GetObjectItem(root, "name");
if (name) {
printf("Name: %s\n", name->valuestring);
}
cJSON_Delete(root);
}
return 0;
}
4.3.5 cJSON_GetObjectItemCaseSensitive
#include <stdio.h>
#include "cJSON.h"
int main() {
const char *json_string = "{\"Name\":\"John\", \"Age\":30}";
cJSON *root = cJSON_Parse(json_string);
if (root && cJSON_IsObject(root)) {
cJSON *name = cJSON_GetObjectItemCaseSensitive(root, "Name");
if (name) {
printf("Name: %s\n", name->valuestring);
}
cJSON_Delete(root);
}
return 0;
}
4.3.6 cJSON_HasObjectItem
#include <stdio.h>
#include "cJSON.h"
int main() {
const char *json_string = "{\"name\":\"John\", \"age\":30}";
cJSON *root = cJSON_Parse(json_string);
if (root && cJSON_IsObject(root)) {
if (cJSON_HasObjectItem(root, "name")) {
cJSON *name = cJSON_GetObjectItem(root, "name");
printf("Name: %s\n", name->valuestring);
}
cJSON_Delete(root);
}
return 0;
}
4.3.7 cJSON_GetErrorPtr
#include <stdio.h>
#include "cJSON.h"
int main() {
const char *json_string = "{\"name\":\"John\", \"age\":30";// 这里故意缺少一个右花括号
cJSON *root = cJSON_Parse(json_string);
if (!root) {
const char *error_ptr = cJSON_GetErrorPtr();
if (error_ptr) {
fprintf(stderr, "Error before: %s\n", error_ptr);
}
}
return 0;
}
4.4
4.4.1 cJSON_GetStringValue
#include <stdio.h>
#include "cJSON.h"
int main() {
const char *json_string = "{\"name\":\"John\"}";
cJSON *root = cJSON_Parse(json_string);
if (root && cJSON_IsObject(root)) {
cJSON *name_item = cJSON_GetObjectItem(root, "name");
if (name_item) {
char *name = cJSON_GetStringValue(name_item);
if (name) {
printf("The name is: %s\n", name);
}
}
cJSON_Delete(root);
}
return 0;
}
4.4.2 cJSON_GetNumberValue
#include <stdio.h>
#include "cJSON.h"
int main() {
const char *json_string = "{\"age\":30}";
cJSON *root = cJSON_Parse(json_string);
if (root && cJSON_IsObject(root)) {
cJSON *age_item = cJSON_GetObjectItem(root, "age");
if (age_item) {
double age = cJSON_GetNumberValue(age_item);
printf("The age is: %.0f\n", age);
}
cJSON_Delete(root);
}
return 0;
}
4.4.3 cJSON_IsInvalid
#include <stdio.h>
#include "cJSON.h"
int main() {
const char *json_string = "{\"name\":\"John\", \"age\":30";// 这里故意造成解析错误
cJSON *root = cJSON_Parse(json_string);
if (cJSON_IsInvalid(root)) {
printf("The cJSON structure is invalid.\n");
} else {
// 如果有效则进行正常操作
//...
cJSON_Delete(root);
}
return 0;
}
4.4.4 cJSON_IsFalse
#include <stdio.h>
#include "cJSON.h"
int main() {
const char *json_string = "{\"is_active\": false}";
cJSON *root = cJSON_Parse(json_string);
if (root && cJSON_IsObject(root)) {
cJSON *is_active_item = cJSON_GetObjectItem(root, "is_active");
if (cJSON_IsFalse(is_active_item)) {
printf("The flag is false.\n");
}
cJSON_Delete(root);
}
return 0;
}
4.4.5 cJSON_IsTrue
#include <stdio.h>
#include "cJSON.h"
int main() {
const char *json_string = "{\"is_enabled\": true}";
cJSON *root = cJSON_Parse(json_string);
if (root && cJSON_IsObject(root)) {
cJSON *is_enabled_item = cJSON_GetObjectItem(root, "is_enabled");
if (cJSON_IsTrue(is_enabled_item)) {
printf("The flag is true.\n");
}
cJSON_Delete(root);
}
return 0;
}
4.4.6 cJSON_IsBool
#include <stdio.h>
#include "cJSON.h"
int main() {
const char *json_string = "{\"is_admin\": true, \"name\":\"John\"}";
cJSON *root = cJSON_Parse(json_string);
if (root && cJSON_IsObject(root)) {
cJSON *is_admin_item = cJSON_GetObjectItem(root, "is_admin");
if (cJSON_IsBool(is_admin_item)) {
if (cJSON_IsTrue(is_admin_item)) {
printf("The user is an admin.\n");
} else {
printf("The user is not an admin.\n");
}
}
cJSON_Delete(root);
}
return 0;
}
4.4.7 cJSON_IsNull
#include <stdio.h>
#include "cJSON.h"
int main() {
const char *json_string = "{\"address\": null, \"name\":\"John\"}";
cJSON *root = cJSON_Parse(json_string);
if (root && cJSON_IsObject(root)) {
cJSON *address_item = cJSON_GetObjectItem(root, "address");
if (cJSON_IsNull(address_item)) {
printf("The address is null.\n");
}
cJSON_Delete(root);
}
return 0;
}
4.4.8 cJSON_IsNumber
#include <stdio.h>
#include "cJSON.h"
int main() {
const char *json_string = "{\"price\": 10.5, \"name\":\"Product\"}";
cJSON *root = cJSON_Parse(json_string);
if (root && cJSON_IsObject(root)) {
cJSON *price_item = cJSON_GetObjectItem(root, "price");
if (cJSON_IsNumber(price_item)) {
double price = cJSON_GetNumberValue(price_item);
printf("The price is: %.2f\n", price);
}
cJSON_Delete(root);
}
return 0;
}
4.4.9 cJSON_IsString
#include <stdio.h>
#include "cJSON.h"
int main() {
const char *json_string = "{\"description\": \"This is a product\", \"id\":1}";
cJSON *root = cJSON_Parse(json_string);
if (root && cJSON_IsObject(root)) {
cJSON *description_item = cJSON_GetObjectItem(root, "description");
if (cJSON_IsString(description_item)) {
char *description = cJSON_GetStringValue(description_item);
printf("The description is: %s\n", description);
}
cJSON_Delete(root);
}
return 0;
}
4.4.10 cJSON_IsArray
#include <stdio.h>
#include "cJSON.h"
int main() {
const char *json_string = "{\"products\":[{\"name\":\"Product1\", \"price\":10}, {\"name\":\"Product2\", \"price\":20}]}";
cJSON *root = cJSON_Parse(json_string);
if (root && cJSON_IsObject(root)) {
cJSON *products_item = cJSON_GetObjectItem(root, "products");
if (cJSON_IsArray(products_item)) {
int size = cJSON_GetArraySize(products_item);
for (int i = 0; i < size; i++) {
cJSON *product = cJSON_GetArrayItem(products_item, i);
if (cJSON_IsObject(product)) {
cJSON *name_item = cJSON_GetObjectItem(product, "name");
if (name_item && cJSON_IsString(name_item)) {
char *name = cJSON_GetStringValue(name_item);
printf("Product name: %s\n", name);
}
}
}
}
cJSON_Delete(root);
}
return 0;
}
4.4.11 cJSON_IsObject
#include <stdio.h>
#include "cJSON.h"
int main() {
const char *json_string = "{\"user\":{\"name\":\"John\", \"age\":30}}";
cJSON *root = cJSON_Parse(json_string);
if (root && cJSON_IsObject(root)) {
cJSON *user_item = cJSON_GetObjectItem(root, "user");
if (cJSON_IsObject(user_item)) {
cJSON *name_item = cJSON_GetObjectItem(user_item, "name");
if (name_item && cJSON_IsString(name_item)) {
char *name = cJSON_GetStringValue(name_item);
printf("User name: %s\n", name);
}
}
cJSON_Delete(root);
}
return 0;
}
4.4.12 cJSON_IsRaw
#include <stdio.h>
#include "cJSON.h"
int main() {
const char *json_string = "{\"raw_data\":\"<some_raw_content>\", \"name\":\"John\"}";
cJSON *root = cJSON_Parse(json_string);
if (root && cJSON_IsObject(root)) {
cJSON *raw_data_item = cJSON_GetObjectItem(root, "raw_data");
if (cJSON_IsRaw(raw_data_item)) {
// 进行针对原始类型数据的特殊处理
//...
}
cJSON_Delete(root);
}
return 0;
}
4.5
4.5.1 cJSON_CreateNull
#include "cJSON.h"
int main() {
cJSON *nullItem = cJSON_CreateNull();
// 这里可以将nullItem添加到一个更大的JSON结构中，例如一个对象或者数组
cJSON_Delete(nullItem);
return 0;
}
4.5.2 cJSON_CreateTrue
#include "cJSON.h"
int main() {
cJSON *trueItem = cJSON_CreateTrue();
// 可以将trueItem添加到一个JSON对象或者数组中
cJSON_Delete(trueItem);
return 0;
}
4.5.3 cJSON_CreateFalse
#include "cJSON.h"
int main() {
cJSON *falseItem = cJSON_CreateFalse();
// 将falseItem整合到一个JSON结构中
cJSON_Delete(falseItem);
return 0;
}
4.5.4 cJSON_CreateBool
#include "cJSON.h"
int main() {
cJSON_bool myBool = false;
cJSON *boolItem = cJSON_CreateBool(myBool);
// 对boolItem进行后续处理，如添加到其他JSON结构
cJSON_Delete(boolItem);
return 0;
}
4.5.5 cJSON_CreateNumber
#include "cJSON.h"
int main() {
double num = 3.14;
cJSON *numberItem = cJSON_CreateNumber(num);
// 将numberItem添加到一个JSON对象或者数组中
cJSON_Delete(numberItem);
return 0;
}
4.5.6 cJSON_CreateString
#include "cJSON.h"
int main() {
const char *str = "Hello, World!";
cJSON *stringItem = cJSON_CreateString(str);
// 把stringItem添加到一个JSON结构中
cJSON_Delete(stringItem);
return 0;
}
4.5.7 cJSON_CreateRaw
#include "cJSON.h"
int main() {
const char *rawJson = "{\"subObject\":\"value\"}";
cJSON *rawItem = cJSON_CreateRaw(rawJson);
// 将rawItem添加到一个JSON对象或者数组中
cJSON_Delete(rawItem);
return 0;
}
4.5.8 cJSON_CreateArray
#include "cJSON.h"
int main() {
cJSON *arrayItem = cJSON_CreateArray();
// 可以向arrayItem中添加其他的cJSON项，如数字、字符串等
cJSON_Delete(arrayItem);
return 0;
}
4.5.9 cJSON_CreateObject
#include "cJSON.h"
int main() {
cJSON *objectItem = cJSON_CreateObject();
// 可以向objectItem中添加键值对，如添加一个姓名属性
cJSON_AddItemToObject(objectItem, "name", cJSON_CreateString("John"));
cJSON_Delete(objectItem);
return 0;
}
4.6
4.6.1 cJSON_CreateStringReference
#include "cJSON.h"
int main() {
const char *myString = "This is a test string";
cJSON *stringRefItem = cJSON_CreateStringReference(myString);
// 使用stringRefItem构建更大的JSON结构或者进行其他操作
cJSON_Delete(stringRefItem);
return 0;
}
4.6.2 cJSON_CreateObjectReference
#include "cJSON.h"
int main() {
cJSON *childObject = cJSON_CreateObject();
cJSON_AddItemToObject(childObject, "name", cJSON_CreateString("Child"));
cJSON *objectRef = cJSON_CreateObjectReference(childObject);
// 使用objectRef构建更大的JSON结构或者进行其他操作
cJSON_Delete(objectRef);
cJSON_Delete(childObject);
return 0;
}
4.6.3 cJSON_CreateArrayReference
#include "cJSON.h"
int main() {
cJSON *childItem = cJSON_CreateNumber(5);
cJSON *arrayRef = cJSON_CreateArrayReference(childItem);
// 使用arrayRef构建更大的JSON结构或者进行其他操作
cJSON_Delete(arrayRef);
cJSON_Delete(childItem);
return 0;
}
4.6.4 cJSON_CreateIntArray
#include "cJSON.h"
int main() {
int numbers[] = {1, 2, 3};
int count = sizeof(numbers)/sizeof(numbers[0]);
cJSON *intArray = cJSON_CreateIntArray(numbers, count);
// 将intArray添加到一个更大的JSON结构中或者进行其他操作
cJSON_Delete(intArray);
return 0;
}
4.6.5 cJSON_CreateFloatArray
#include "cJSON.h"
int main() {
float numbers[] = {1.1f, 2.2f, 3.3f};
int count = sizeof(numbers)/sizeof(numbers[0]);
cJSON *floatArray = cJSON_CreateFloatArray(numbers, count);
// 对floatArray进行后续操作，如添加到其他JSON结构
cJSON_Delete(floatArray);
return 0;
}
4.6.6 cJSON_CreateDoubleArray
#include "cJSON.h"
int main() {
double numbers[] = {1.1, 2.2, 3.3};
int count = sizeof(numbers)/sizeof(numbers[0]);
cJSON *doubleArray = cJSON_CreateDoubleArray(numbers, count);
// 处理doubleArray，如将其整合到一个JSON对象中
cJSON_Delete(doubleArray);
return 0;
}
4.6.7 cJSON_CreateStringArray
#include "cJSON.h"
int main() {
const char *strings[] = {"apple", "banana", "cherry"};
int count = sizeof(strings)/sizeof(strings[0]);
cJSON *stringArray = cJSON_CreateStringArray(strings, count);
// 对stringArray进行操作，如添加到一个JSON对象中
cJSON_Delete(stringArray);
return 0;
}
4.7
4.7.1 cJSON_AddItemToArray
#include "cJSON.h"
int main() {
cJSON *array = cJSON_CreateArray();
cJSON *item = cJSON_CreateNumber(42);
if (cJSON_AddItemToArray(array, item)) {
char *jsonString = cJSON_Print(array);
printf("%s\n", jsonString);
free(jsonString);
}
cJSON_Delete(array);
return 0;
}
4.7.2 cJSON_AddItemToObject
#include "cJSON.h"
int main() {
cJSON *object = cJSON_CreateObject();
cJSON *nameItem = cJSON_CreateString("John");
if (cJSON_AddItemToObject(object, "name", nameItem)) {
char *jsonString = cJSON_Print(object);
printf("%s\n", jsonString);
free(jsonString);
}
cJSON_Delete(object);
return 0;
}
4.7.3 cJSON_AddItemToObjectCS
#include "cJSON.h"
int main() {
cJSON *object = cJSON_CreateObject();
cJSON *valueItem = cJSON_CreateNumber(100);
const char *key = "constant_key";
if (cJSON_AddItemToObjectCS(object, key, valueItem)) {
char *jsonString = cJSON_Print(object);
printf("%s\n", jsonString);
free(jsonString);
}
cJSON_Delete(object);
return 0;
}
4.7.4 cJSON_AddItemReferenceToArray
#include "cJSON.h"
int main() {
cJSON *array = cJSON_CreateArray();
cJSON *sharedItem = cJSON_CreateString("Shared data");
if (cJSON_AddItemReferenceToArray(array, sharedItem)) {
char *jsonString = cJSON_Print(array);
printf("%s\n", jsonString);
free(jsonString);
}
cJSON_Delete(array);
return 0;
}
4.7.5 cJSON_AddItemReferenceToObject
#include "cJSON.h"
int main() {
cJSON *object = cJSON_CreateObject();
cJSON *sharedObject = cJSON_CreateObject();
cJSON_AddItemToObject(sharedObject, "city", cJSON_CreateString("New York"));
const char *key = "address";
if (cJSON_AddItemReferenceToObject(object, key, sharedObject)) {
char *jsonString = cJSON_Print(object);
printf("%s\n", jsonString);
free(jsonString);
}
cJSON_Delete(object);
return 0;
}
4.8
4.8.1 cJSON_DetachItemViaPointer
#include "cJSON.h"
int main() {
cJSON *array = cJSON_CreateArray();
cJSON *item = cJSON_CreateNumber(42);
cJSON_AddItemToArray(array, item);
cJSON *detachedItem = cJSON_DetachItemViaPointer(array, item);
if (detachedItem) {
// 可以对detachedItem进行操作，例如修改它的值
cJSON *newArray = cJSON_CreateArray();
cJSON_AddItemToArray(newArray, detachedItem);
char *jsonString = cJSON_Print(newArray);
printf("%s\n", jsonString);
free(jsonString);
cJSON_Delete(newArray);
}
cJSON_Delete(array);
return 0;
}
4.8.2 cJSON_DetachItemFromArray
#include "cJSON.h"
int main() {
cJSON *array = cJSON_CreateArray();
cJSON *item1 = cJSON_CreateNumber(10);
cJSON *item2 = cJSON_CreateNumber(20);
cJSON_AddItemToArray(array, item1);
cJSON_AddItemToArray(array, item2);
cJSON *detachedItem = cJSON_DetachItemFromArray(array, 0);
if (detachedItem) {
char *jsonString = cJSON_Print(detachedItem);
printf("%s\n", jsonString);
free(jsonString);
// 可以重新将detachedItem插入到其他地方或者修改后再插回原数组
}
cJSON_Delete(array);
return 0;
}
4.8.3 cJSON_DeleteItemFromArray
#include "cJSON.h"
int main() {
cJSON *array = cJSON_CreateArray();
cJSON *item1 = cJSON_CreateNumber(10);
cJSON *item2 = cJSON_CreateNumber(20);
cJSON_AddItemToArray(array, item1);
cJSON_AddItemToArray(array, item2);
cJSON_DeleteItemFromArray(array, 0);
char *jsonString = cJSON_Print(array);
printf("%s\n", jsonString);
free(jsonString);
cJSON_Delete(array);
return 0;
}
4.8.4 cJSON_DetachItemFromObject
#include "cJSON.h"
int main() {
cJSON *object = cJSON_CreateObject();
cJSON *value = cJSON_CreateString("red");
cJSON_AddItemToObject(object, "color_preference", value);
cJSON *detachedValue = cJSON_DetachItemFromObject(object, "color_preference");
if (detachedValue) {
char *jsonString = cJSON_Print(detachedValue);
printf("%s\n", jsonString);
free(jsonString);
// 可以对detachedValue进行操作，如修改后再插回原对象
}
cJSON_Delete(object);
return 0;
}
4.8.5 cJSON_DetachItemFromObjectCaseSensitive
#include "cJSON.h"
int main() {
cJSON *object = cJSON_CreateObject();
cJSON *value = cJSON_CreateString("red");
cJSON_AddItemToObject(object, "Color_Preference", value);
cJSON *detachedValue = cJSON_DetachItemFromObjectCaseSensitive(object, "Color_Preference");
if (detachedValue) {
char *jsonString = cJSON_Print(detachedValue);
printf("%s\n", jsonString);
free(jsonString);
// 可以对detachedValue进行操作，如修改后再插回原对象
}
cJSON_Delete(object);
return 0;
}
4.8.6 cJSON_DeleteItemFromObject
#include "cJSON.h"
int main() {
cJSON *object = cJSON_CreateObject();
cJSON *value = cJSON_CreateString("abc123");
cJSON_AddItemToObject(object, "temporary_token", value);
cJSON_DeleteItemFromObject(object, "temporary_token");
char *jsonString = cJSON_Print(object);
printf("%s\n", jsonString);
free(jsonString);
cJSON_Delete(object);
return 0;
}
4.8.7 cJSON_DeleteItemFromObjectCaseSensitive
#include "cJSON.h"
int main() {
cJSON *object = cJSON_CreateObject();
cJSON *value = cJSON_CreateString("abc123");
cJSON_AddItemToObject(object, "Temporary_Token", value);
cJSON_DeleteItemFromObjectCaseSensitive(object, "Temporary_Token");
char *jsonString = cJSON_Print(object);
printf("%s\n", jsonString);
free(jsonString);
cJSON_Delete(object);
return 0;
}
4.9
4.9.1 cJSON_InsertItemInArray
#include <stdio.h>
#include <cJSON/cJSON.h>
int main() {
// 创建一个空的cJSON数组
cJSON *array = cJSON_CreateArray();
if (!array) {
perror("Failed to create array");
return 1;
}
// 创建一个新的cJSON项
cJSON *newItem = cJSON_CreateString("new element");
if (!newItem) {
perror("Failed to create new item");
cJSON_Delete(array);
return 1;
}
// 在数组的开头（位置0）插入新项
if (!cJSON_InsertItemInArray(array, 0, newItem)) {
perror("Failed to insert item in array");
cJSON_Delete(array);
cJSON_Delete(newItem);
return 1;
}
char *jsonString = cJSON_Print(array);
printf("The array after insertion: %s\n", jsonString);
cJSON_Delete(array);
cJSON_free(jsonString);
return 0;
}
4.9.2 cJSON_ReplaceItemViaPointer
#include <stdio.h>
#include <cJSON/cJSON.h>
int main() {
// 创建一个父对象
cJSON *parent = cJSON_CreateObject();
if (!parent) {
perror("Failed to create parent object");
return 1;
}
// 在父对象中创建一个子项
cJSON *originalItem = cJSON_CreateString("original value");
cJSON_AddItemToObject(parent, "key", originalItem);
// 创建一个新的替换项
cJSON *replacementItem = cJSON_CreateString("replacement value");
// 通过指针替换子项
if (!cJSON_ReplaceItemViaPointer(parent, originalItem, replacementItem)) {
perror("Failed to replace item via pointer");
cJSON_Delete(parent);
cJSON_Delete(originalItem);
cJSON_Delete(replacementItem);
return 1;
}
char *jsonString = cJSON_Print(parent);
printf("The object after replacement: %s\n", jsonString);
cJSON_Delete(parent);
cJSON_free(jsonString);
return 0;
}
4.9.3 cJSON_ReplaceItemInArray
#include <stdio.h>
#include <cJSON/cJSON.h>
int main() {
// 创建一个cJSON数组并添加一些元素
cJSON *array = cJSON_CreateArray();
cJSON *item1 = cJSON_CreateString("element1");
cJSON *item2 = cJSON_CreateString("element2");
cJSON_AddItemToArray(array, item1);
cJSON_AddItemToArray(array, item2);
// 创建一个新的替换项
cJSON *newItem = cJSON_CreateString("new element2");
// 替换数组中的第二个元素（位置1）
if (!cJSON_ReplaceItemInArray(array, 1, newItem)) {
perror("Failed to replace item in array");
cJSON_Delete(array);
cJSON_Delete(item1);
cJSON_Delete(item2);
cJSON_Delete(newItem);
return 1;
}
char *jsonString = cJSON_Print(array);
printf("The array after replacement: %s\n", jsonString);
cJSON_Delete(array);
cJSON_free(jsonString);
return 0;
}
4.9.4 cJSON_ReplaceItemInObject
#include <stdio.h>
#include <cJSON/cJSON.h>
int main() {
// 创建一个cJSON对象
cJSON *object = cJSON_CreateObject();
if (!object) {
perror("Failed to create object");
return 1;
}
// 在对象中添加一个键值对
cJSON *originalItem = cJSON_CreateString("original value");
cJSON_AddItemToObject(object, "key", originalItem);
// 创建一个新的替换项
cJSON *newItem = cJSON_CreateString("replacement value");
// 替换对象中键为"key"的项
if (!cJSON_ReplaceItemInObject(object, "key", newItem)) {
perror("Failed to replace item in object");
cJSON_Delete(object);
cJSON_Delete(originalItem);
cJSON_Delete(newItem);
return 1;
}
char *jsonString = cJSON_Print(object);
printf("The object after replacement: %s\n", jsonString);
cJSON_Delete(object);
cJSON_free(jsonString);
return 0;
}
4.9.5 cJSON_ReplaceItemInObjectCaseSensitive
#include <stdio.h>
#include <cJSON/cJSON.h>
int main() {
// 创建一个cJSON对象
cJSON *object = cJSON_CreateObject();
if (!object) {
perror("Failed to create object");
return 1;
}
// 在对象中添加一个键值对，键为"Key"（大写K）
cJSON *originalItem = cJSON_CreateString("original value");
cJSON_AddItemToObject(object, "Key", originalItem);
// 创建一个新的替换项
cJSON *newItem = cJSON_CreateString("replacement value");
// 尝试替换对象中键为"key"（小写k）的项，由于区分大小写，替换会失败
if (!cJSON_ReplaceItemInObjectCaseSensitive(object, "key", newItem)) {
printf("Replacement failed as keys are case - sensitive\n");
}
char *jsonString = cJSON_Print(object);
printf("The object: %s\n", jsonString);
cJSON_Delete(object);
cJSON_free(jsonString);
return 0;
}
4.10
4.10.1 cJSON_Duplicate
#include <stdio.h>
#include <cJSON.h>
int main() {
// 创建一个简单的cJSON对象
cJSON *root = cJSON_CreateObject();
cJSON_AddNumberToObject(root, "number", 10);
cJSON *duplicated = cJSON_Duplicate(root, 1);
if (duplicated) {
char *duplicated_str = cJSON_Print(duplicated);
printf("Duplicated JSON: %s\n", duplicated_str);
cJSON_Delete(duplicated);
free(duplicated_str);
}
cJSON_Delete(root);
return 0;
}
4.10.2 cJSON_Compare
#include <stdio.h>
#include <cJSON.h>
int main() {
cJSON *obj1 = cJSON_CreateObject();
cJSON_AddStringToObject(obj1, "name", "John");
cJSON_AddNumberToObject(obj1, "age", 30);
cJSON *obj2 = cJSON_CreateObject();
cJSON_AddStringToObject(obj2, "name", "John");
cJSON_AddNumberToObject(obj2, "age", 30);
cJSON_bool equal = cJSON_Compare(obj1, obj2, 1);
if (equal) {
printf("The two cJSON objects are equal.\n");
} else {
printf("The two cJSON objects are not equal.\n");
}
cJSON_Delete(obj1);
cJSON_Delete(obj2);
return 0;
}
4.10.3 cJSON_Minify
#include <stdio.h>
#include <cJSON.h>
int main() {
char json_str[] = "{\n\t\"name\": \"John\",\n\t\"age\": 30\n}";
cJSON_Minify(json_str);
printf("Minified JSON: %s\n", json_str);
return 0;
}
4.11
4.11.1 cJSON_AddNullToObject
#include <stdio.h>
#include <cJSON.h>
int main() {
cJSON *root = cJSON_CreateObject();
cJSON *null_item = cJSON_AddNullToObject(root, "nullable_field");
if (null_item) {
char *json_str = cJSON_Print(root);
printf("JSON with null value: %s\n", json_str);
cJSON_Delete(root);
free(json_str);
}
return 0;
}
4.11.2 cJSON_AddTrueToObject
#include <stdio.h>
#include <cJSON.h>
int main() {
cJSON *root = cJSON_CreateObject();
cJSON *true_item = cJSON_AddTrueToObject(root, "is_logged_in");
if (true_item) {
char *json_str = cJSON_Print(root);
printf("JSON with true value: %s\n", json_str);
cJSON_Delete(root);
free(json_str);
}
return 0;
}
4.11.3 cJSON_AddFalseToObject
#include <stdio.h>
#include <cJSON.h>
int main() {
cJSON *root = cJSON_CreateObject();
cJSON *false_item = cJSON_AddFalseToObject(root, "is_feature_enabled");
if (false_item) {
char *json_str = cJSON_Print(root);
printf("JSON with false value: %s\n", json_str);
cJSON_Delete(root);
free(json_str);
}
return 0;
}
4.11.4 cJSON_AddBoolToObject
#include <stdio.h>
#include <cJSON.h>
int main() {
cJSON *root = cJSON_CreateObject();
cJSON_bool user_permission = 1;
cJSON *bool_item = cJSON_AddBoolToObject(root, "can_edit", user_permission);
if (bool_item) {
char *json_str = cJSON_Print(root);
printf("JSON with boolean value: %s\n", json_str);
cJSON_Delete(root);
free(json_str);
}
return 0;
}
4.11.5 cJSON_AddNumberToObject
#include <stdio.h>
#include <cJSON.h>
int main() {
cJSON *root = cJSON_CreateObject();
double price = 19.99;
cJSON *number_item = cJSON_AddNumberToObject(root, "price", price);
if (number_item) {
char *json_str = cJSON_Print(root);
printf("JSON with number value: %s\n", json_str);
cJSON_Delete(root);
free(json_str);
}
return 0;
}
4.11.6 cJSON_AddStringToObject
#include <stdio.h>
#include <cJSON.h>
int main() {
cJSON *root = cJSON_CreateObject();
char *name = "John";
cJSON *string_item = cJSON_AddStringToObject(root, "name", name);
if (string_item) {
char *json_str = cJSON_Print(root);
printf("JSON with string value: %s\n", json_str);
cJSON_Delete(root);
free(json_str);
}
return 0;
}
4.11.7 cJSON_AddRawToObject
#include <stdio.h>
#include <cJSON.h>
int main() {
cJSON *root = cJSON_CreateObject();
char *raw = "{\"custom\":\"data\"}";
cJSON *raw_item = cJSON_AddRawToObject(root, "custom_data", raw);
if (raw_item) {
char *json_str = cJSON_Print(root);
printf("JSON with raw value: %s\n", json_str);
cJSON_Delete(root);
free(json_str);
}
return 0;
}
4.11.8 cJSON_AddObjectToObject
#include <stdio.h>
#include <cJSON.h>
int main() {
cJSON *root = cJSON_CreateObject();
cJSON *sub_object = cJSON_AddObjectToObject(root, "department");
if (sub_object) {
cJSON_AddStringToObject(sub_object, "name", "Sales");
char *json_str = cJSON_Print(root);
printf("JSON with sub - object: %s\n", json_str);
cJSON_Delete(root);
free(json_str);
}
return 0;
}
4.11.9 cJSON_AddArrayToObject
#include <stdio.h>
#include <cJSON.h>
int main() {
cJSON *root = cJSON_CreateObject();
cJSON *array = cJSON_AddArrayToObject(root, "phone_numbers");
if (array) {
cJSON_AddStringToObject(array, "", "123 - 456 - 7890");
char *json_str = cJSON_Print(root);
printf("JSON with array: %s\n", json_str);
cJSON_Delete(root);
free(json_str);
}
return 0;
}
4.12
4.12.1 cJSON_SetIntValue
#include <stdio.h>
#include "cJSON.h"
int main() {
cJSON *user_info = cJSON_CreateObject();
int age = 25;
cJSON_SetIntValue(user_info, age);
// 可以通过以下方式验证设置是否成功
if (user_info!= NULL) {
printf("Valueint: %d, Valuedouble: %lf\n", user_info->valueint, user_info->valuedouble);
}
cJSON_Delete(user_info);
return 0;
}
4.12.2 cJSON_SetNumberValue
#include <stdio.h>
#include "cJSON.h"
int main() {
cJSON *trade_info = cJSON_CreateObject();
double price = 12.5;
cJSON_SetNumberValue(trade_info, price);
if (trade_info!= NULL) {
// 假设可以通过某种方式获取设置后的数值进行验证
double retrieved_price;
// 这里只是示例，实际获取方式可能不同
retrieved_price = trade_info->valuedouble;
printf("Set price: %lf, Retrieved price: %lf\n", price, retrieved_price);
}
cJSON_Delete(trade_info);
return 0;
}
4.12.3 cJSON_SetValuestring
#include <stdio.h>
#include "cJSON.h"
int main() {
cJSON *user_info = cJSON_CreateString("John");
cJSON_SetValuestring(user_info, "Mike");
if (user_info!= NULL) {
printf("New valuestring: %s\n", user_info->valuestring);
}
cJSON_Delete(user_info);
return 0;
}
4.12.4 cJSON_SetBoolValue
#include <stdio.h>
#include "cJSON.h"
int main() {
cJSON *feature_status = cJSON_CreateTrue();
cJSON_SetBoolValue(feature_status, false);
if (feature_status!= NULL) {
if (feature_status->type == cJSON_False) {
printf("Feature is now disabled.\n");
} else {
printf("Feature is enabled.\n");
}
}
cJSON_Delete(feature_status);
return 0;
}
4.12.5 cJSON_ArrayForEach
#include <stdio.h>
#include "cJSON.h"
int main() {
cJSON *array = cJSON_CreateArray();
cJSON_AddItemToArray(array, cJSON_CreateNumber(1));
cJSON_AddItemToArray(array, cJSON_CreateNumber(2));
cJSON_AddItemToArray(array, cJSON_CreateNumber(3));
cJSON *element;
cJSON_ArrayForEach(element, array) {
if (element!= NULL) {
printf("%lf ", element->valuedouble);
}
}
printf("\n");
cJSON_Delete(array);
return 0;
}
4.13
4.13.1 cJSON_malloc、cJSON_free
#include <stdio.h>
#include "cJSON.h"
int main() {
// 使用cJSON_malloc分配内存
cJSON *new_obj = (cJSON *)cJSON_malloc(sizeof(cJSON));
if (new_obj!= NULL) {
// 进行一些初始化操作，这里省略
// 使用完毕后释放内存
cJSON_free(new_obj);
}
return 0;
}